Add basic zfs ioc input nvpair validation

We want newer versions of libzfs_core to run against an existing
zfs kernel module (i.e. a deferred reboot or module reload after
an update).

Programmatically document, via a zfs_ioc_key_t, the valid arguments 
for the ioc commands that rely on nvpair input arguments (i.e. non 
legacy commands from libzfs_core). Automatically verify the expected 
pairs before dispatching a command.

This initial phase focuses on the non-legacy ioctls. A follow-on 
change can address the legacy ioctl input from the zfs_cmd_t.

The zfs_ioc_key_t for zfs_keys_channel_program looks like:

static const zfs_ioc_key_t zfs_keys_channel_program[] = {
       {"program",     DATA_TYPE_STRING,               0},
       {"arg",         DATA_TYPE_UNKNOWN,              0},
       {"sync",        DATA_TYPE_BOOLEAN_VALUE,        ZK_OPTIONAL},
       {"instrlimit",  DATA_TYPE_UINT64,               ZK_OPTIONAL},
       {"memlimit",    DATA_TYPE_UINT64,               ZK_OPTIONAL},
};

Introduce four input errors to identify specific input failures
(in addition to generic argument value errors like EINVAL, ERANGE, 
EBADF, and E2BIG).

ZFS_ERR_IOC_CMD_UNAVAIL the ioctl number is not supported by kernel
ZFS_ERR_IOC_ARG_UNAVAIL an input argument is not supported by kernel
ZFS_ERR_IOC_ARG_REQUIRED a required input argument is missing
ZFS_ERR_IOC_ARG_BADTYPE an input argument has an invalid type

Reviewed-by: Matthew Ahrens <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Don Brady <[email protected]>
Closes #7780 

1 files changed, 92 insertions, 84 deletions

diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 7daf72895..c8c7cebae 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013, 2017 Joyent, Inc. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
@@ -1078,6 +1078,8 @@ typedef struct ddt_histogram {
 
 /*
  * /dev/zfs ioctl numbers.
+ *
+ * These numbers cannot change over time. New ioctl numbers must be appended.
  */
 typedef enum zfs_ioc {
 	/*
@@ -1085,93 +1087,93 @@ typedef enum zfs_ioc {
 	 */
 	ZFS_IOC_FIRST =	('Z' << 8),
 	ZFS_IOC = ZFS_IOC_FIRST,
-	ZFS_IOC_POOL_CREATE = ZFS_IOC_FIRST,
-	ZFS_IOC_POOL_DESTROY,
-	ZFS_IOC_POOL_IMPORT,
-	ZFS_IOC_POOL_EXPORT,
-	ZFS_IOC_POOL_CONFIGS,
-	ZFS_IOC_POOL_STATS,
-	ZFS_IOC_POOL_TRYIMPORT,
-	ZFS_IOC_POOL_SCAN,
-	ZFS_IOC_POOL_FREEZE,
-	ZFS_IOC_POOL_UPGRADE,
-	ZFS_IOC_POOL_GET_HISTORY,
-	ZFS_IOC_VDEV_ADD,
-	ZFS_IOC_VDEV_REMOVE,
-	ZFS_IOC_VDEV_SET_STATE,
-	ZFS_IOC_VDEV_ATTACH,
-	ZFS_IOC_VDEV_DETACH,
-	ZFS_IOC_VDEV_SETPATH,
-	ZFS_IOC_VDEV_SETFRU,
-	ZFS_IOC_OBJSET_STATS,
-	ZFS_IOC_OBJSET_ZPLPROPS,
-	ZFS_IOC_DATASET_LIST_NEXT,
-	ZFS_IOC_SNAPSHOT_LIST_NEXT,
-	ZFS_IOC_SET_PROP,
-	ZFS_IOC_CREATE,
-	ZFS_IOC_DESTROY,
-	ZFS_IOC_ROLLBACK,
-	ZFS_IOC_RENAME,
-	ZFS_IOC_RECV,
-	ZFS_IOC_SEND,
-	ZFS_IOC_INJECT_FAULT,
-	ZFS_IOC_CLEAR_FAULT,
-	ZFS_IOC_INJECT_LIST_NEXT,
-	ZFS_IOC_ERROR_LOG,
-	ZFS_IOC_CLEAR,
-	ZFS_IOC_PROMOTE,
-	ZFS_IOC_SNAPSHOT,
-	ZFS_IOC_DSOBJ_TO_DSNAME,
-	ZFS_IOC_OBJ_TO_PATH,
-	ZFS_IOC_POOL_SET_PROPS,
-	ZFS_IOC_POOL_GET_PROPS,
-	ZFS_IOC_SET_FSACL,
-	ZFS_IOC_GET_FSACL,
-	ZFS_IOC_SHARE,
-	ZFS_IOC_INHERIT_PROP,
-	ZFS_IOC_SMB_ACL,
-	ZFS_IOC_USERSPACE_ONE,
-	ZFS_IOC_USERSPACE_MANY,
-	ZFS_IOC_USERSPACE_UPGRADE,
-	ZFS_IOC_HOLD,
-	ZFS_IOC_RELEASE,
-	ZFS_IOC_GET_HOLDS,
-	ZFS_IOC_OBJSET_RECVD_PROPS,
-	ZFS_IOC_VDEV_SPLIT,
-	ZFS_IOC_NEXT_OBJ,
-	ZFS_IOC_DIFF,
-	ZFS_IOC_TMP_SNAPSHOT,
-	ZFS_IOC_OBJ_TO_STATS,
-	ZFS_IOC_SPACE_WRITTEN,
-	ZFS_IOC_SPACE_SNAPS,
-	ZFS_IOC_DESTROY_SNAPS,
-	ZFS_IOC_POOL_REGUID,
-	ZFS_IOC_POOL_REOPEN,
-	ZFS_IOC_SEND_PROGRESS,
-	ZFS_IOC_LOG_HISTORY,
-	ZFS_IOC_SEND_NEW,
-	ZFS_IOC_SEND_SPACE,
-	ZFS_IOC_CLONE,
-	ZFS_IOC_BOOKMARK,
-	ZFS_IOC_GET_BOOKMARKS,
-	ZFS_IOC_DESTROY_BOOKMARKS,
-	ZFS_IOC_CHANNEL_PROGRAM,
-	ZFS_IOC_RECV_NEW,
-	ZFS_IOC_POOL_SYNC,
-	ZFS_IOC_LOAD_KEY,
-	ZFS_IOC_UNLOAD_KEY,
-	ZFS_IOC_CHANGE_KEY,
-	ZFS_IOC_REMAP,
-	ZFS_IOC_POOL_CHECKPOINT,
-	ZFS_IOC_POOL_DISCARD_CHECKPOINT,
+	ZFS_IOC_POOL_CREATE = ZFS_IOC_FIRST,	/* 0x5a00 */
+	ZFS_IOC_POOL_DESTROY,			/* 0x5a01 */
+	ZFS_IOC_POOL_IMPORT,			/* 0x5a02 */
+	ZFS_IOC_POOL_EXPORT,			/* 0x5a03 */
+	ZFS_IOC_POOL_CONFIGS,			/* 0x5a04 */
+	ZFS_IOC_POOL_STATS,			/* 0x5a05 */
+	ZFS_IOC_POOL_TRYIMPORT,			/* 0x5a06 */
+	ZFS_IOC_POOL_SCAN,			/* 0x5a07 */
+	ZFS_IOC_POOL_FREEZE,			/* 0x5a08 */
+	ZFS_IOC_POOL_UPGRADE,			/* 0x5a09 */
+	ZFS_IOC_POOL_GET_HISTORY,		/* 0x5a0a */
+	ZFS_IOC_VDEV_ADD,			/* 0x5a0b */
+	ZFS_IOC_VDEV_REMOVE,			/* 0x5a0c */
+	ZFS_IOC_VDEV_SET_STATE,			/* 0x5a0d */
+	ZFS_IOC_VDEV_ATTACH,			/* 0x5a0e */
+	ZFS_IOC_VDEV_DETACH,			/* 0x5a0f */
+	ZFS_IOC_VDEV_SETPATH,			/* 0x5a10 */
+	ZFS_IOC_VDEV_SETFRU,			/* 0x5a11 */
+	ZFS_IOC_OBJSET_STATS,			/* 0x5a12 */
+	ZFS_IOC_OBJSET_ZPLPROPS,		/* 0x5a13 */
+	ZFS_IOC_DATASET_LIST_NEXT,		/* 0x5a14 */
+	ZFS_IOC_SNAPSHOT_LIST_NEXT,		/* 0x5a15 */
+	ZFS_IOC_SET_PROP,			/* 0x5a16 */
+	ZFS_IOC_CREATE,				/* 0x5a17 */
+	ZFS_IOC_DESTROY,			/* 0x5a18 */
+	ZFS_IOC_ROLLBACK,			/* 0x5a19 */
+	ZFS_IOC_RENAME,				/* 0x5a1a */
+	ZFS_IOC_RECV,				/* 0x5a1b */
+	ZFS_IOC_SEND,				/* 0x5a1c */
+	ZFS_IOC_INJECT_FAULT,			/* 0x5a1d */
+	ZFS_IOC_CLEAR_FAULT,			/* 0x5a1e */
+	ZFS_IOC_INJECT_LIST_NEXT,		/* 0x5a1f */
+	ZFS_IOC_ERROR_LOG,			/* 0x5a20 */
+	ZFS_IOC_CLEAR,				/* 0x5a21 */
+	ZFS_IOC_PROMOTE,			/* 0x5a22 */
+	ZFS_IOC_SNAPSHOT,			/* 0x5a23 */
+	ZFS_IOC_DSOBJ_TO_DSNAME,		/* 0x5a24 */
+	ZFS_IOC_OBJ_TO_PATH,			/* 0x5a25 */
+	ZFS_IOC_POOL_SET_PROPS,			/* 0x5a26 */
+	ZFS_IOC_POOL_GET_PROPS,			/* 0x5a27 */
+	ZFS_IOC_SET_FSACL,			/* 0x5a28 */
+	ZFS_IOC_GET_FSACL,			/* 0x5a29 */
+	ZFS_IOC_SHARE,				/* 0x5a2a */
+	ZFS_IOC_INHERIT_PROP,			/* 0x5a2b */
+	ZFS_IOC_SMB_ACL,			/* 0x5a2c */
+	ZFS_IOC_USERSPACE_ONE,			/* 0x5a2d */
+	ZFS_IOC_USERSPACE_MANY,			/* 0x5a2e */
+	ZFS_IOC_USERSPACE_UPGRADE,		/* 0x5a2f */
+	ZFS_IOC_HOLD,				/* 0x5a30 */
+	ZFS_IOC_RELEASE,			/* 0x5a31 */
+	ZFS_IOC_GET_HOLDS,			/* 0x5a32 */
+	ZFS_IOC_OBJSET_RECVD_PROPS,		/* 0x5a33 */
+	ZFS_IOC_VDEV_SPLIT,			/* 0x5a34 */
+	ZFS_IOC_NEXT_OBJ,			/* 0x5a35 */
+	ZFS_IOC_DIFF,				/* 0x5a36 */
+	ZFS_IOC_TMP_SNAPSHOT,			/* 0x5a37 */
+	ZFS_IOC_OBJ_TO_STATS,			/* 0x5a38 */
+	ZFS_IOC_SPACE_WRITTEN,			/* 0x5a39 */
+	ZFS_IOC_SPACE_SNAPS,			/* 0x5a3a */
+	ZFS_IOC_DESTROY_SNAPS,			/* 0x5a3b */
+	ZFS_IOC_POOL_REGUID,			/* 0x5a3c */
+	ZFS_IOC_POOL_REOPEN,			/* 0x5a3d */
+	ZFS_IOC_SEND_PROGRESS,			/* 0x5a3e */
+	ZFS_IOC_LOG_HISTORY,			/* 0x5a3f */
+	ZFS_IOC_SEND_NEW,			/* 0x5a40 */
+	ZFS_IOC_SEND_SPACE,			/* 0x5a41 */
+	ZFS_IOC_CLONE,				/* 0x5a42 */
+	ZFS_IOC_BOOKMARK,			/* 0x5a43 */
+	ZFS_IOC_GET_BOOKMARKS,			/* 0x5a44 */
+	ZFS_IOC_DESTROY_BOOKMARKS,		/* 0x5a45 */
+	ZFS_IOC_CHANNEL_PROGRAM,		/* 0x5a46 */
+	ZFS_IOC_RECV_NEW,			/* 0x5a47 */
+	ZFS_IOC_POOL_SYNC,			/* 0x5a48 */
+	ZFS_IOC_LOAD_KEY,			/* 0x5a49 */
+	ZFS_IOC_UNLOAD_KEY,			/* 0x5a4a */
+	ZFS_IOC_CHANGE_KEY,			/* 0x5a4b */
+	ZFS_IOC_REMAP,				/* 0x5a4c */
+	ZFS_IOC_POOL_CHECKPOINT,		/* 0x5a4d */
+	ZFS_IOC_POOL_DISCARD_CHECKPOINT,	/* 0x5a4e */
 
 	/*
 	 * Linux - 3/64 numbers reserved.
 	 */
 	ZFS_IOC_LINUX = ('Z' << 8) + 0x80,
-	ZFS_IOC_EVENTS_NEXT,
-	ZFS_IOC_EVENTS_CLEAR,
-	ZFS_IOC_EVENTS_SEEK,
+	ZFS_IOC_EVENTS_NEXT,			/* 0x5a81 */
+	ZFS_IOC_EVENTS_CLEAR,			/* 0x5a82 */
+	ZFS_IOC_EVENTS_SEEK,			/* 0x5a83 */
 
 	/*
 	 * FreeBSD - 1/64 numbers reserved.
@@ -1193,13 +1195,19 @@ typedef enum zfs_ioc {
  * The enum implicitly includes all the error codes from errno.h.
  * New code should use and extend this enum for errors that are
  * not described precisely by generic errno codes.
+ *
+ * These numbers should not change over time. New entries should be appended.
  */
 typedef enum {
 	ZFS_ERR_CHECKPOINT_EXISTS = 1024,
 	ZFS_ERR_DISCARDING_CHECKPOINT,
 	ZFS_ERR_NO_CHECKPOINT,
 	ZFS_ERR_DEVRM_IN_PROGRESS,
-	ZFS_ERR_VDEV_TOO_BIG
+	ZFS_ERR_VDEV_TOO_BIG,
+	ZFS_ERR_IOC_CMD_UNAVAIL,
+	ZFS_ERR_IOC_ARG_UNAVAIL,
+	ZFS_ERR_IOC_ARG_REQUIRED,
+	ZFS_ERR_IOC_ARG_BADTYPE,
 } zfs_errno_t;
 
 /*